As the frequency of operation of communications equipment gets higher and higher, and as more and more data needs to be transmitted, the requirements on the detection and demodulation equipment increase. Further, when multilevel signals, as opposed to binary signals, need to be detected, more problems in accurate detection of bit information are introduced. When the communications equipment is transmitting data, as contrasted with voice information, the bit error rate must be very low. The radio which incorporates the present invention, required two separate data streams which had to be delay matched. If the two data streams were not accurately delay matched, the bit error rate at the output would rise to unacceptable levels. The present invention, therefore, was designed to provide a dynamic timing adjustment whereby the analog-to-digital conversion would take place at the optimal time or at a time that would cause the "eye" of an oscilloscope presentation of the analog signal to be maximum. The present invention accomplishes the adjustment by utilizing the most significant error bit (next most significant bit output by the A/D converter and not used as part of the digitally converted word), adjusts its polarity in view of the most recent history of amplitude variation of the incoming analog signal to be converted and uses this logically modified signal in an integrator circuit to adjust the amount of time delay of a clock signal to either lessen or increase the delay to adjust the clock signal toward the optimal action triggering conversion point.
It is therefore an object of the present invention to provide a dynamic timing adjustment circuit for a multilevel analog signal A/D converter.